Keychain flashlights have been known for a long time, and became increasingly popular with the introduction of high-efficiency light emitting diode (LED) bulbs. LED bulbs can be powered by one or more “coin” cells, and can emit a high intensity beam of light. Depending on the particular LED used, an LED keychain flashlight can emit light in any of a variety of colors, such as white, red, blue and green.
These miniature flashlights are typically designed so that they can be removably attached to a key ring. Some have a case containing the power source, the LED and a switch, and a chain connecting the case to a snap hook which can removably receive a key ring. Others have one element of the snap hook formed as an integral part of the case, and the other element of the snap hook hinged to the case and urged toward a closed position by a spring, so that the combination takes the form of a so-called “carabiner” ring, which can be opened readily for removal from, or attachment to, a key ring.
The carabiner type key ring LED flashlight obviates the chain used in some keychain flashlights to connect the snap hook to the case. However, the carabiner type key ring flashlight is somewhat less flexible than the chain type. Thus, in using a carabiner type key ring flashlight to illuminate a door lock at night, it is often necessary to remove the flashlight from the key ring, since often the key cannot be inserted into the lock while the light is directed at the lock. The carabiner type flashlight can be readily removed from the key ring, but in order to make easy removal in the dark possible, the structure of the carabiner type snap hook is necessarily somewhat bulky, making the overall size of the flashlight structure large and unwieldy. Moreover, the assembly of the carabiner type device is somewhat difficult because it entails the installation of a spring needed to urge the movable element of the snap hook toward its closed condition.